1. Field of the Invention
This invention relates to an endoscope apparatus adapted to meter NMR.
2. Related Art Statement
Conventionally, in detecting and diagnosing a cuticle cancer or the like generated on the inner surface of a digestive organ of a human body or particularly in the upper layer part of a stomach wall, there has been a general method wherein the generating position is detected with an endoscope or X-ray photographing and the living body tissue of such position is collected and is diagnosed to be bad or not. However, in such conventional method, there have been problems that the sample collecting position is in a range so comparatively wide that the diagnosis can not be immediately made, that the toil of collecting the living body tissue is very large and that the human body is damaged.
On the other hand, against it, recently, there has come to be developed a non-attacking human body diagnosing method utilizing a nuclear magnetic resonance (abbreviated as NMR hereinafter) phenomenon. For example, in an NMR imaging apparatus utilizing the above mentioned NMR phenomenon, a human body is placed in a magnetic field, a high frequency (magnetic field) of a predetermined frequency is given to the human body, a nucleus having a spin within the human body is excited and an NMR signal of a predetermined frequency from this excited nucleus is sensed and is processed with a computer to obtain a sectioned image. The sectioned image obtained by this NMR imaging apparatus is very useful for diagnosing a cancer or the like. That is to say, generally, the NMR signals obtained from a cancer cell and normal cell are known to be different in the relieving time. The diagnosis of whether it is a cancer or not is made possible by measuring this relieving time.
However, in the above mentioned NMR imaging apparatus, in order to obtain a sectioned image, enormous NMR signals must be processed, a high speed large capacity computer is required and the entire apparatus becomes large and expensive.
Conventionally, at the time of the endoscope observation, in case a visually abnormal part is discovered whether this abnormal part is, for example, bad or not will be desired to be judged to some extent. However, for such above mentioned NMR imaging apparatus is expensive and large and that further it is difficult to make the part recognized to be visually abnormal and the sectioned image correspond to each other.
In order to cope with it, as shown, for example, in the gazette of a Japanese patent application laid open No. 88140/1984, there is suggested an NMR endoscope wherein, in the tip part of an endoscope insertable part, a high frequency magnetic field is formed and a high frequency coil (antenna) detecting NMR signals is provided. According to this NMR endoscope, when the above mentioned antenna is pressed against an abnormal position and the NMR signal of the abnormal position is detected, the physiological variation of this abnormal position, for example, whether it is a cancer or not can be detected and diagnosed.
Now, in the conventional MNR endoscope, the antenna is contained within the endoscope tip part body. However, as the above mentioned antenna is comparatively large and the above mentioned tip part is required to be fine in the diameter, it has been difficult to incorporate the antenna within the tip part without making the tip part large. Therefore, the above mentioned antenna has not been able to be easily led into a body.
A catheter or endoscope provided in the tip part with a coil is disclosed in the gazette of a Japanese patent application laid open No. 500048/1987 (international laid open No. W086/01093). However, in case only the catheter provided with the coil is led into a body, it will be difficult to confirm the NMR metering position. In case the coil is incorporated in the tip part of the endoscope, the tip part will become large as described above.
Generally, a ferromagnetic field is required to meter NMR. Therefore, in the endoscope to be used to meter NMR, at least the insertable part is arranged in a ferromagnetic field.
In the conventional endoscope, most of the curvable tube forming the curvable part, wires for curving the curvable part, flex (spiral tube) and blade (net tube) have used an inartensitic stainless steel to be a ferromagnetic material. When the insertable part is formed of such ferromagnetic material, in case it is used within a ferromagnetic field, it will be influenced by the magnetic field, the operation of smoothly inserting the insertable part into the body will be obstructed and it will be difficult to lead it into the object position. Within the magnetic field for NMR, the insertable part reacts so strongly on this magnetic field as to have been difficult to use within a body cavity.
In an endoscope containing an antenna in the tip part, in case NMR is metered with the antenna pressed against a living body tissue, the region in which NMR is being metered has not been able to be confirmed. Also, the visual field has not been able to be secured with the above mentioned antenna pressed against the living body tissue.
In case a diseased part within a body cavity is to be NMR-metered through an endoscope, unless the antenna is pressed against an object position, for example, for several tens of seconds to several minutes, no accurate metering will be able to be made. However, in an endoscope containing an antenna in the tip part, it has been difficult to fix the above mentioned antenna in an object position.
Now, there is a case that an antenna is inserted into a body cavity through an endoscope to meter NMR from within the body and such NMR apparatus for observing an NMR image from without the body as an NMR imaging apparatus is used simultaneously to observe NMR from without the body. However, as the antenna to be inserted into the body cavity is conventionally made of a metal, when the NMR image from without the body is to be observed with this antenna as inserted within the body cavity, the magnetic field of the NMR apparatus for observing from without the body will be disturbed and no good picture image will be obtained. Therefore, in case the NMR image from without the body is to be observed, it will be necessary to pull out the endoscope and the operation will be complicated.
In the above mentioned antenna, it is desirable to make the detecting direction coincide with the direction of the high frequency magnetic field made by this antenna itself. However, in the conventional NMR endoscope, as the antenna is fixed to the tip part, it has been difficult to make the detecting direction coincide with the high frequency magnetic field.